Condenser and Condensing Units - AAON · PDF fileCF Series Condenser and Condensing Units...
Transcript of Condenser and Condensing Units - AAON · PDF fileCF Series Condenser and Condensing Units...
CF Series
Condenser and Condensing Units
Installation Operation
amp Maintenance
If the information in this manual is not followed exactly a fire or explosion may result causing property damage personal injury or loss of life
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
FOR YOUR SAFETY
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance
WARNING
2
Table of Contents
AAON CF Series Features and Options Introduction 5 Safety 6 CF Series Feature String Nomenclature 11 General Information 14
Codes and Ordinances 14
Receiving Unit 14 Storage 15 Wiring Diagrams 16 General Maintenance 16
Installation 17
Forklifting the Unit 17 Lifting the Unit 18
Locating the Unit 18
Mounting Isolation 19 Access Doors 19 Low Ambient Operation 19
Fan Cycling Low Ambient 20 Variable Speed Low Ambient 20 Flooded Condenser Low Ambient 20
LAC Valve 20 Condenser Flooding 21
Refrigerant Piping 22 Determining Refrigerant Line Size 22 Liquid Line 23
Suction Line 24
Discharge Line 26 Hot Gas Bypass Line 28 Hot Gas Reheat 29
Electrical 30 Startup 32
Compressor Operation 32 Variable Capacity Compressor Controller 33 Low Voltage Terminals 33 High Voltage Terminals 33 Compressor Lockouts 35
Maintenance 36 General 36
Compressors 36 Refrigerant Filter Driers 36 Adjusting Refrigerant Charge 36 Lubrication 40 Condenser Tube Inspection 40
Maintenance Recommendations 40 E-Coated Coil Cleaning 40 Service 42
3
Warranties 42
Replacement Parts 42 AAON - Longview Warranty Service and Parts Department 42
Split System Refrigerant Piping Diagrams 43
Index of Tables and Figures
Tables
Table 1 ndashClearances for Proper Operation 18 Table 2 ndash Clearances for Coil Pull 18 Table 3 - Condenser Flooding 21 Table 4 - Demand Signal vs Compressor Capacity Modulation 34
Table 5 - Thermistor Temperature vs Resistance Values 35 Table 6 - Max Filter Drier Pressure Drops 36
Table 7 - Acceptable Refrigeration Circuit Values 37
Table 8 - R-410A Refrigerant Temperature-Pressure Chart 39
Figures
Figure 1 - Forklifting a CF Series A Cabinet 17
Figure 2 - Forklifting a CF Series B and C Cabinet 17 Figure 3 ndash Lifting Details and Orientation of a CF Series 9-70 ton Condensing Unit 18
Figure 4 - Orientation of Series 2-7 ton Condensing Unit 18 Figure 5 - Adjustable Fan Cycling Switch 20 Figure 6 - Piping Schematic of Example System using the LAC Valve 21
Figure 7 - Double Suction Riser Construction 25
Figure 8 ndash Heat Pump Piping Schematic of Suction Vapor Flow Down in Double Riser 27 Figure 9 ndash Heat Pump Piping Schematic of Discharge Vapor Flow Up in Double Riser 27 Figure 10 ndash Oil Return Line 28
Figure 11 - Variable Capacity Compressor Controller 33 Figure 12 - Compressor Controller Flash Code Details 34
Figure 13 - Adjustable compressor lockout 35 Figure 14 - Ambient sensor cover 35 Figure 15 - AC Split System Piping Suction Down 43 Figure 16 - AC Split System Piping Suction Up 44 Figure 17 - AC with LAC Split System Piping Suction Down 45
Figure 18 - AC with LAC Split System Piping Suction Up 46 Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down 47 Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up 48
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down 49 Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up 50 Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down 51 Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up 52
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down 53 Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up 54
4
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down 55 Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up 56
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down 57 Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up 58 Figure 31 - Heat Pump Split System Piping Suction Down 59
Figure 32 - Heat Pump Split System Piping Suction Up 60 Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down 61 Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up 62 Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down 63
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up 64 Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down 65 Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up 66
V45040 Rev A 171016
(ACP J00424)
5
AAON CF Series Features and Options Introduction
Energy Efficiency
bull Staged Two-Step 10-100 Variable
Capacity or Tandem R-410A Scroll
Compressors
bull Air-Source Heat Pump
bull VFD Controlled or ECM Driven
Condenser Fans
Humidity Control bull Modulating Hot Gas Reheat
Safety bull Phase and Brownout Protection
bull Adjustable Compressor Lockout
Installation and Maintenance bull Isolated Controls and Compressor
Compartment
bull Access Doors with Full Length Stainless
Steel Piano Hinges
bull Molded Lockable Handles
bull Run Test Report and Installation Manual
Included in Controls Compartment
bull Color-Coded Wiring and Wiring
Diagrams
bull Factory Installed Convenience Outlet
bull Service Access Lights
bull Remote StartStop Terminals
bull Liquid Line Sight Glass
bull Compressor Isolation Valves
System Integration bull Complete Split System with AAON DX
Air Handling Units
bull Single Point Non-Fused Disconnect
Power Switch
bull Labeled Split System Piping Stub Outs
with Shut-Off Valves
bull Flooded Condenser 0degF Low Ambient
Controls
bull Terminal Block for Thermostat with
Isolation Relays
bull Constant Air Volume (CAV) Makeup
Air (MUA) Variable Air Volume
(VAV) and Single Zone Variable Air
Volume (SZ VAV)
Environmentally Friendly bull R-410A Refrigerant
Extended Life bull Optional 5 Year Compressor Warranty
bull G90 Galvanized Steel Construction
bull 2500 Hour Salt Spray Tested Exterior
Corrosion Protection
bull 6000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils
bull Copper Fin and Stainless Steel Casing
Coils
bull Condenser Coil Guards
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
2
Table of Contents
AAON CF Series Features and Options Introduction 5 Safety 6 CF Series Feature String Nomenclature 11 General Information 14
Codes and Ordinances 14
Receiving Unit 14 Storage 15 Wiring Diagrams 16 General Maintenance 16
Installation 17
Forklifting the Unit 17 Lifting the Unit 18
Locating the Unit 18
Mounting Isolation 19 Access Doors 19 Low Ambient Operation 19
Fan Cycling Low Ambient 20 Variable Speed Low Ambient 20 Flooded Condenser Low Ambient 20
LAC Valve 20 Condenser Flooding 21
Refrigerant Piping 22 Determining Refrigerant Line Size 22 Liquid Line 23
Suction Line 24
Discharge Line 26 Hot Gas Bypass Line 28 Hot Gas Reheat 29
Electrical 30 Startup 32
Compressor Operation 32 Variable Capacity Compressor Controller 33 Low Voltage Terminals 33 High Voltage Terminals 33 Compressor Lockouts 35
Maintenance 36 General 36
Compressors 36 Refrigerant Filter Driers 36 Adjusting Refrigerant Charge 36 Lubrication 40 Condenser Tube Inspection 40
Maintenance Recommendations 40 E-Coated Coil Cleaning 40 Service 42
3
Warranties 42
Replacement Parts 42 AAON - Longview Warranty Service and Parts Department 42
Split System Refrigerant Piping Diagrams 43
Index of Tables and Figures
Tables
Table 1 ndashClearances for Proper Operation 18 Table 2 ndash Clearances for Coil Pull 18 Table 3 - Condenser Flooding 21 Table 4 - Demand Signal vs Compressor Capacity Modulation 34
Table 5 - Thermistor Temperature vs Resistance Values 35 Table 6 - Max Filter Drier Pressure Drops 36
Table 7 - Acceptable Refrigeration Circuit Values 37
Table 8 - R-410A Refrigerant Temperature-Pressure Chart 39
Figures
Figure 1 - Forklifting a CF Series A Cabinet 17
Figure 2 - Forklifting a CF Series B and C Cabinet 17 Figure 3 ndash Lifting Details and Orientation of a CF Series 9-70 ton Condensing Unit 18
Figure 4 - Orientation of Series 2-7 ton Condensing Unit 18 Figure 5 - Adjustable Fan Cycling Switch 20 Figure 6 - Piping Schematic of Example System using the LAC Valve 21
Figure 7 - Double Suction Riser Construction 25
Figure 8 ndash Heat Pump Piping Schematic of Suction Vapor Flow Down in Double Riser 27 Figure 9 ndash Heat Pump Piping Schematic of Discharge Vapor Flow Up in Double Riser 27 Figure 10 ndash Oil Return Line 28
Figure 11 - Variable Capacity Compressor Controller 33 Figure 12 - Compressor Controller Flash Code Details 34
Figure 13 - Adjustable compressor lockout 35 Figure 14 - Ambient sensor cover 35 Figure 15 - AC Split System Piping Suction Down 43 Figure 16 - AC Split System Piping Suction Up 44 Figure 17 - AC with LAC Split System Piping Suction Down 45
Figure 18 - AC with LAC Split System Piping Suction Up 46 Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down 47 Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up 48
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down 49 Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up 50 Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down 51 Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up 52
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down 53 Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up 54
4
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down 55 Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up 56
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down 57 Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up 58 Figure 31 - Heat Pump Split System Piping Suction Down 59
Figure 32 - Heat Pump Split System Piping Suction Up 60 Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down 61 Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up 62 Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down 63
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up 64 Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down 65 Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up 66
V45040 Rev A 171016
(ACP J00424)
5
AAON CF Series Features and Options Introduction
Energy Efficiency
bull Staged Two-Step 10-100 Variable
Capacity or Tandem R-410A Scroll
Compressors
bull Air-Source Heat Pump
bull VFD Controlled or ECM Driven
Condenser Fans
Humidity Control bull Modulating Hot Gas Reheat
Safety bull Phase and Brownout Protection
bull Adjustable Compressor Lockout
Installation and Maintenance bull Isolated Controls and Compressor
Compartment
bull Access Doors with Full Length Stainless
Steel Piano Hinges
bull Molded Lockable Handles
bull Run Test Report and Installation Manual
Included in Controls Compartment
bull Color-Coded Wiring and Wiring
Diagrams
bull Factory Installed Convenience Outlet
bull Service Access Lights
bull Remote StartStop Terminals
bull Liquid Line Sight Glass
bull Compressor Isolation Valves
System Integration bull Complete Split System with AAON DX
Air Handling Units
bull Single Point Non-Fused Disconnect
Power Switch
bull Labeled Split System Piping Stub Outs
with Shut-Off Valves
bull Flooded Condenser 0degF Low Ambient
Controls
bull Terminal Block for Thermostat with
Isolation Relays
bull Constant Air Volume (CAV) Makeup
Air (MUA) Variable Air Volume
(VAV) and Single Zone Variable Air
Volume (SZ VAV)
Environmentally Friendly bull R-410A Refrigerant
Extended Life bull Optional 5 Year Compressor Warranty
bull G90 Galvanized Steel Construction
bull 2500 Hour Salt Spray Tested Exterior
Corrosion Protection
bull 6000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils
bull Copper Fin and Stainless Steel Casing
Coils
bull Condenser Coil Guards
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
3
Warranties 42
Replacement Parts 42 AAON - Longview Warranty Service and Parts Department 42
Split System Refrigerant Piping Diagrams 43
Index of Tables and Figures
Tables
Table 1 ndashClearances for Proper Operation 18 Table 2 ndash Clearances for Coil Pull 18 Table 3 - Condenser Flooding 21 Table 4 - Demand Signal vs Compressor Capacity Modulation 34
Table 5 - Thermistor Temperature vs Resistance Values 35 Table 6 - Max Filter Drier Pressure Drops 36
Table 7 - Acceptable Refrigeration Circuit Values 37
Table 8 - R-410A Refrigerant Temperature-Pressure Chart 39
Figures
Figure 1 - Forklifting a CF Series A Cabinet 17
Figure 2 - Forklifting a CF Series B and C Cabinet 17 Figure 3 ndash Lifting Details and Orientation of a CF Series 9-70 ton Condensing Unit 18
Figure 4 - Orientation of Series 2-7 ton Condensing Unit 18 Figure 5 - Adjustable Fan Cycling Switch 20 Figure 6 - Piping Schematic of Example System using the LAC Valve 21
Figure 7 - Double Suction Riser Construction 25
Figure 8 ndash Heat Pump Piping Schematic of Suction Vapor Flow Down in Double Riser 27 Figure 9 ndash Heat Pump Piping Schematic of Discharge Vapor Flow Up in Double Riser 27 Figure 10 ndash Oil Return Line 28
Figure 11 - Variable Capacity Compressor Controller 33 Figure 12 - Compressor Controller Flash Code Details 34
Figure 13 - Adjustable compressor lockout 35 Figure 14 - Ambient sensor cover 35 Figure 15 - AC Split System Piping Suction Down 43 Figure 16 - AC Split System Piping Suction Up 44 Figure 17 - AC with LAC Split System Piping Suction Down 45
Figure 18 - AC with LAC Split System Piping Suction Up 46 Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down 47 Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up 48
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down 49 Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up 50 Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down 51 Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up 52
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down 53 Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up 54
4
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down 55 Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up 56
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down 57 Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up 58 Figure 31 - Heat Pump Split System Piping Suction Down 59
Figure 32 - Heat Pump Split System Piping Suction Up 60 Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down 61 Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up 62 Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down 63
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up 64 Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down 65 Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up 66
V45040 Rev A 171016
(ACP J00424)
5
AAON CF Series Features and Options Introduction
Energy Efficiency
bull Staged Two-Step 10-100 Variable
Capacity or Tandem R-410A Scroll
Compressors
bull Air-Source Heat Pump
bull VFD Controlled or ECM Driven
Condenser Fans
Humidity Control bull Modulating Hot Gas Reheat
Safety bull Phase and Brownout Protection
bull Adjustable Compressor Lockout
Installation and Maintenance bull Isolated Controls and Compressor
Compartment
bull Access Doors with Full Length Stainless
Steel Piano Hinges
bull Molded Lockable Handles
bull Run Test Report and Installation Manual
Included in Controls Compartment
bull Color-Coded Wiring and Wiring
Diagrams
bull Factory Installed Convenience Outlet
bull Service Access Lights
bull Remote StartStop Terminals
bull Liquid Line Sight Glass
bull Compressor Isolation Valves
System Integration bull Complete Split System with AAON DX
Air Handling Units
bull Single Point Non-Fused Disconnect
Power Switch
bull Labeled Split System Piping Stub Outs
with Shut-Off Valves
bull Flooded Condenser 0degF Low Ambient
Controls
bull Terminal Block for Thermostat with
Isolation Relays
bull Constant Air Volume (CAV) Makeup
Air (MUA) Variable Air Volume
(VAV) and Single Zone Variable Air
Volume (SZ VAV)
Environmentally Friendly bull R-410A Refrigerant
Extended Life bull Optional 5 Year Compressor Warranty
bull G90 Galvanized Steel Construction
bull 2500 Hour Salt Spray Tested Exterior
Corrosion Protection
bull 6000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils
bull Copper Fin and Stainless Steel Casing
Coils
bull Condenser Coil Guards
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
4
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down 55 Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up 56
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down 57 Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up 58 Figure 31 - Heat Pump Split System Piping Suction Down 59
Figure 32 - Heat Pump Split System Piping Suction Up 60 Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down 61 Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up 62 Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down 63
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up 64 Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down 65 Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up 66
V45040 Rev A 171016
(ACP J00424)
5
AAON CF Series Features and Options Introduction
Energy Efficiency
bull Staged Two-Step 10-100 Variable
Capacity or Tandem R-410A Scroll
Compressors
bull Air-Source Heat Pump
bull VFD Controlled or ECM Driven
Condenser Fans
Humidity Control bull Modulating Hot Gas Reheat
Safety bull Phase and Brownout Protection
bull Adjustable Compressor Lockout
Installation and Maintenance bull Isolated Controls and Compressor
Compartment
bull Access Doors with Full Length Stainless
Steel Piano Hinges
bull Molded Lockable Handles
bull Run Test Report and Installation Manual
Included in Controls Compartment
bull Color-Coded Wiring and Wiring
Diagrams
bull Factory Installed Convenience Outlet
bull Service Access Lights
bull Remote StartStop Terminals
bull Liquid Line Sight Glass
bull Compressor Isolation Valves
System Integration bull Complete Split System with AAON DX
Air Handling Units
bull Single Point Non-Fused Disconnect
Power Switch
bull Labeled Split System Piping Stub Outs
with Shut-Off Valves
bull Flooded Condenser 0degF Low Ambient
Controls
bull Terminal Block for Thermostat with
Isolation Relays
bull Constant Air Volume (CAV) Makeup
Air (MUA) Variable Air Volume
(VAV) and Single Zone Variable Air
Volume (SZ VAV)
Environmentally Friendly bull R-410A Refrigerant
Extended Life bull Optional 5 Year Compressor Warranty
bull G90 Galvanized Steel Construction
bull 2500 Hour Salt Spray Tested Exterior
Corrosion Protection
bull 6000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils
bull Copper Fin and Stainless Steel Casing
Coils
bull Condenser Coil Guards
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
5
AAON CF Series Features and Options Introduction
Energy Efficiency
bull Staged Two-Step 10-100 Variable
Capacity or Tandem R-410A Scroll
Compressors
bull Air-Source Heat Pump
bull VFD Controlled or ECM Driven
Condenser Fans
Humidity Control bull Modulating Hot Gas Reheat
Safety bull Phase and Brownout Protection
bull Adjustable Compressor Lockout
Installation and Maintenance bull Isolated Controls and Compressor
Compartment
bull Access Doors with Full Length Stainless
Steel Piano Hinges
bull Molded Lockable Handles
bull Run Test Report and Installation Manual
Included in Controls Compartment
bull Color-Coded Wiring and Wiring
Diagrams
bull Factory Installed Convenience Outlet
bull Service Access Lights
bull Remote StartStop Terminals
bull Liquid Line Sight Glass
bull Compressor Isolation Valves
System Integration bull Complete Split System with AAON DX
Air Handling Units
bull Single Point Non-Fused Disconnect
Power Switch
bull Labeled Split System Piping Stub Outs
with Shut-Off Valves
bull Flooded Condenser 0degF Low Ambient
Controls
bull Terminal Block for Thermostat with
Isolation Relays
bull Constant Air Volume (CAV) Makeup
Air (MUA) Variable Air Volume
(VAV) and Single Zone Variable Air
Volume (SZ VAV)
Environmentally Friendly bull R-410A Refrigerant
Extended Life bull Optional 5 Year Compressor Warranty
bull G90 Galvanized Steel Construction
bull 2500 Hour Salt Spray Tested Exterior
Corrosion Protection
bull 6000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils
bull Copper Fin and Stainless Steel Casing
Coils
bull Condenser Coil Guards
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
6
ELECTRIC SHOCK Electric shock hazard Before servicing shut off all electrical power to the unit including remote disconnects to avoid shock hazard or injury from rotating parts Follow proper Lockout-Tagout procedures
WARNING
Safety
Attention should be paid to the following statements
NOTE - Notes are intended to clarify the unit installation operation and maintenance
CAUTION - Caution statements are given to prevent actions that may result in
equipment damage property damage or personal injury
WARNING - Warning statements are given to prevent actions that could result in
equipment damage property damage personal injury or death
DANGER - Danger statements are given to prevent actions that will result in equipment
damage property damage severe personal injury or death
QUALIFIED INSTALLER Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician A copy of this IOM should be kept with the unit
WARNING
ELECTRIC SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury death or property damage Improper servicing could result in dangerous operation serious injury death or property damage When servicing controls label all
wires prior to disconnecting Reconnect wires correctly
Verify proper operation after servicing Secure all doors with key-lock or nut and bolt
WARNING
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
7
ROTATING COMPONENTS Unit contains fans with moving parts that can cause serious injury Do not remove grill containing fans until the power to the unit has been disconnected and fan has stopped rotating
WARNING
LIVE ELECTRICAL During installation testing servicing and troubleshooting of the equipment it may be necessary to work with live electrical components Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks Standard NFPA-70E an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn should be followed
WARNING
FIRE EXPLOSION OR CARBON MONOXIDE POISONING HAZARD Failure to replace proper controls could result in fire explosion or carbon monoxide poisoning Failure to follow safety warnings exactly could result in serious injury death or property damage Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance
WARNING
GROUNDING REQUIRED All field installed wiring must be completed by qualified personnel Field installed wiring must comply with NECCEC local and state electrical code requirements Failure to follow code requirements could result in serious injury or death Provide proper unit ground in accordance with these code requirements
WARNING
VARIABLE FREQUENCY DRIVES
Do not leave VFDs unattended in hand mode or manual bypass Damage to personnel or equipment can occur if left unattended When in hand mode or manual bypass mode VFDs will not respond to controls or alarms
WARNING
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
8
LEAK TESTING
Do not use oxygen acetylene or air in place of refrigerant and dry nitrogen for leak testing A violent explosion may result causing injury or death
WARNING
VARIABLE FREQUENCY DRIVES
Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired Never defeat the VFD motor overload feature The overload ampere setting must not exceed 115 of the electric motors FLA rating as shown on the motor nameplate
CAUTION
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician Scroll compressors are directional and can be damaged if rotated in the wrong direction Compressor rotation must be checked using suction and discharge gauges Fan motor rotation should be checked for proper operation Alterations should only be made at the unit power connection
CAUTION
UNIT HANDLING To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage injury or death
WARNING
DOOR LATCHES
Door compartments containing hazardous voltage or rotating parts are equipped with door latches that allow locks Door latches are shipped with a nut and bolt requiring tooled access If the shipping hardware is not replaced with a pad lock always re-install the nut and bolt after closing the door to maintain tooled access
CAUTION
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
9
ENCLOSED AREA
Do not work in an enclosed area where refrigerant or nitrogen gases may be leaking A sufficient quantity of vapors may be present and cause
injury or death
WARNING
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
COIL CLEANERS
To prevent damage to the unit do not use acidic chemical coil cleaners Do not use alkaline chemical coil cleaners with a pH value greater than 85 after mixing without first using an aluminum corrosion inhibitor in the cleaning solution
CAUTION
COIL CLEANERS
Some chemical coil cleaning compounds are caustic or toxic Use these substances only in accordance with the manufacturerrsquos usage instructions Failure to follow instructions may result in equipment damage injury or death
WARNING
COIL CLEANING
Do not clean DX refrigerant coils with hot water or steam The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil
CAUTION
CONVENIENCE OUTLETS
Factory installed convenience outlets are not intended for use while the unit is operating
WARNING
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
10
1 Startup and service must be performed
by a Factory Trained Service
Technician
2 The unit is for outdoor use only See
General Information section for more
information
3 Every unit has a unique equipment
nameplate with electrical operational
and unit clearance specifications
Always refer to the unit nameplate for
specific ratings unique to the model
purchased
4 READ THE ENTIRE INSTALLATION
OPERATION AND MAINTENANCE
MANUAL OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL
5 Keep this manual and all literature
safeguarded near or on the unit
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJ
RE
V
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
11
CF Series Feature String Nomenclature
MODEL OPTIONS Series and Generation
CF
Major Revision
A
Unit Size
002 = 2 ton Capacity
003 = 3 ton Capacity
004 = 4 ton Capacity
005 = 5 ton Capacity
006 = 6 ton Capacity
007 = 7 ton Capacity
009 = 9 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
015 = 15 ton Capacity
016 = 16 ton Capacity
018 = 18 ton Capacity
020 = 20 ton Capacity
025 = 25 ton Capacity
026 = 26 ton Capacity
030 = 30 ton Capacity
031 = 31 ton Capacity
040 = 40 ton Capacity
050 = 50 ton Capacity
060 = 60 ton Capacity
070 = 70 ton Capacity
Series
A = 2-7 ton units
B = 9-15 ton units
C = 16-25 amp 30 ton units
D = 26 amp 31-70 ton units
Minor Revision
A
Voltage
1 = 230V1Φ60Hz
2 = 230V3Φ60Hz
3 = 460V3Φ60Hz
4 = 575V3Φ60Hz
8 = 208V3Φ60Hz
9 = 208V1Φ60Hz
A1 Compressor Style
0 = Air-Cooled Condenser - No Compressors
(1 Circuit)
A = R-410A Scroll Compressors
B = R-410A Two Step Capacity Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
P = Air-Cooled Condenser - No Compressors
(2 Circuits)
Q = Air-Cooled Condenser - No Compressors
(4 Circuits)
A2 Condenser Style
C = Air-Cooled Condenser
J = Air-Source Heat Pump
A3 Configuration
0 = Standard
A4 Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
G = Copper Fin + Stainless Steel Casing - Condenser
Coil
A5 Staging
0 = No Cooling
G = 1 OnOff Refrigeration System
H = 1 Variable Capacity Refrigeration System
J = 2 OnOff Refrigeration Systems
K = 1 Variable Capacity Refrigeration System + 1
OnOff Refrigeration System
L = 2 Variable Capacity Refrigeration System
R = 4 OnOff Refrigeration Systems
T = 2 Variable Capacity Refrigeration Systems + 2
OnOff Refrigeration Systems
U = 4 Variable Capacity Refrigeration Systems
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
CF Series Feature String Nomenclature
Model Options Unit Feature Options G
EN
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0
0 0 0 0 0 D B
16
17
18
19
20
21
22
12
UNIT FEATURE OPTIONS 1 Unit Orientation
0 = Vertical Condenser Discharge - Standard Access
2A Refrigeration Control
0 = Standard
A = 5 Minute Compressor Off Timer + 20 Second
Compressor Stage Delay
C = Adjustable Fan Cycling
D = Adjustable Compressor Lockout
G = Option A + Adjustable Fan Cycling
H = Option A + Adjustable Compressor Lockout
M = Adjustable Fan Cycling + Adjustable
Compressor Lockout
W = Option A + Adjustable Fan Cycling +
Adjustable Compressor Lockout
2B Blank
0 = Standard
3A Refrigeration Options
0 = Standard
A = Hot Gas Bypass Lead Stage [HGB]
B = HGB Lead + HGB Lag
D = Hot Gas Bypass Non-Variable Capacity
Refrigeration Systems [HGBNV]
E = Modulating Hot Gas Reheat [MHGR]
H = HGB + MHGR
J = HGB Lead + HGB Lag + MHGR
L = HGBNV + MHGR
3B Blank
0 = Standard
4 Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Options A + B
D = Flooded Condenser 0degF Low Ambient Controls ndash
One Circuit
E = Options A + D
F = Options B + D
G = Options A + B + D
H = Flooded Condenser 0degF Low Ambient Controls-
Two Circuits
4 Refrigeration Accessories Continued
J = Options A + H
K = Options B + H
L = Options A + B + H
R = Flooded Condenser 0degF Low Ambient Controls ndash
Four Circuits
S = Options A + R
T = Options B + R
U = Options A + B + R
5 Blank
0 = Standard
6A Unit Disconnect Type
0 = Single Point Power Block
A = Single Point Power Non-Fused Disconnect
6B Disconnect 1 Size
0 = Standard
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
6C Blank
0 = Standard
7 Accessories
0 = Standard
B = Phase amp Brown Out Protection
D = Suction Pressure Transducer on Each
Refrigeration Circuit
E = Compressor Sound Blanket
L = Options B + D
M = Options B + E
Q = Options D + E
1 = Options B + D + E
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
CF Series Feature String Nomenclature
Model Options Unit Feature Options
GE
N
MJR
EV
SIZ
E
SE
RIE
S
MN
RE
V
VL
T
A1
A2
A3
A4
A5
1
2A
2B
3A
3B
4
5
6A
6B
6C
7
8A
8B
8
C
8D
9
10
11
12
13
14
15
CF A - 015 - B - A - 3 - D C 0 0 K 0 - A 0 - E 0 - C 0 - A N 0 - B - D E 0 0 - 0 0 A 0 E 0 0 0 0 0 0 0 D B 1
6
17
18
19
20
21
22
13
8A Control Sequence
A = Terminal Block for Thermostat w Isolation
Relays
D = VAV Unit Controller - VAV Cool + CAV Heat
E = CAV Unit Controller
F = Makeup Air Unit Controller - CAV Cool + CAV
Heat
H = Constant Volume HP Unit Controller - CAV
Cool + CAV Heat
J = Makeup Air HP Unit Controller - CAV Cool +
CAV Heat
N = Field Installed DDC Controls by Others with
Isolation Relays
8B Control Suppliers
0 = Standard
C = WattMaster VCM-X (Main Controller in Air
Handling Unit)
E = WattMaster VCC-X (Main Controller in Air
Handling Unit)
8C Control Supplier Options
0 = Standard
8D BMS Connection amp Diagnostics
0 = Standard
9 Blank
0 = Standard
10 Blank
0 = Standard
11 Maintenance Accessories
0 = Standard
A = Factory Wired 115VAC Convenience Outlet
B = Field Wired 115VAC Convenience Outlet
C = Service Lights
E = Remote Unit StartStop Terminals
F = Options A + C
H = Options A + E
J = Options B + C
L = Options B + E
N = Options C + E
R = Options A + C + E
U = Options B + C + E
12 Code Options
0 = Standard ETL USA Listing
B = ETL USA + Canada Listing
13 Air-Cooled Condenser Accessories
0 = Standard
A = Condenser Coil Guard
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Options A + C
J = Options A + E
14 Blank
0 = Standard
15 Blank
0 = Standard
16 Electrical Options
0 = Standard
17 Shipping Options
0 = Standard
A = Crating
B = Export Crating
18 Blank
0 = Standard
19 Blank
0 = Standard
20 Cabinet Material
0 = Galvanized Steel Cabinet
21 Warranty
0 = Standard
D = Compressor Warranty - Years 2-5
22 Type
B = Premium AAON Gray Paint Exterior
E = Premium AAON Gray Paint Ext + Shrink Wrap
X = SPA + Premium AAON Gray Paint Exterior
1 = SPA + Premium AAON Gray Paint Exterior +
Shrink Wrap
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
14
General Information
AAON CF Series air-cooled condensers and
condensing units have been designed for
outdoor use only They are factory
assembled wired charged and run-tested
Codes and Ordinances
CF Series units have been tested and
certified by ETL in accordance with UL
Safety Standard 1995CSA C222 No 236
System should be sized in accordance with
the American Society of Heating
Refrigeration and Air Conditioning
Engineers Handbook
Installation of CF Series units must conform
to the ICC standards of the International
Mechanical Code the International Building
Code and local building plumbing and
electrical codes All appliances must be
electrically grounded in accordance with
local codes or in the absence of local codes
the current National Electric Code
ANSINFPA 70 or the current Canadian
Electrical Code CSA C221
Receiving Unit
When received the unit should be checked
for damage that might have occurred in
transit If damage is found it should be noted
on the carrierrsquos freight bill A request for
inspection by carrierrsquos agent should be made
in writing at once Nameplate should be
checked to ensure the correct model sizes
and voltages have been received to match
the job requirements
If repairs must be made to damaged goods
then the factory should be notified before
any repair action is taken in order to protect
the warranty Certain equipment alteration
repair and manipulation of equipment
without the manufacturerrsquos consent may
void the product warranty Contact AAON
Warranty Department for assistance with
handling damaged goods repairs and
freight claims (903) 236-4403
NOTE Upon receipt check shipment for
items that ship loose Consult order and
shipment documentation to identify potential
loose-shipped items Loose-shipped items
may have been placed inside the unit cabinet
SHARP EDGES
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Installation and service must be performed by a Factory Trained Service Technician
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty
WARNING
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
15
for security Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access
The warranty card must be completed in full
and returned to AAON not more than 3
months after the unit is delivered
Storage
If installation will not occur immediately
following delivery store equipment in a dry
protected area away from construction
traffic and in the proper orientation as
marked on the packaging with all internal
packaging in place Secure all loose-shipped
items
Failure to observe the following instructions
will result in premature failure of your
system and possible voiding of the
warranty
Never turn off the main power supply to the
unit except for complete shutdown When
power is cut off from the unit any
compressors using crankcase heaters cannot
prevent refrigerant migration This means
the compressor will cool down and liquid
refrigerant may accumulate in the
compressor The compressor is designed to
pump refrigerant gas and damage may occur
if liquid enters the compressor when power
is restored
Before unit operation the main power
switch must be turned on for at least
twenty-four hours for units with compressor
crankcase heaters This will give the
crankcase heater time to clear any liquid
accumulation out of the compressor before it
is required to run
Always control the system from the control
panel never at the main power supply
(except for emergency or for complete
shutdown of the system)
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional ven ting of refrigerant as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed
CAUTION
CRANKCASE HEATER OPERATION
Units are equipped with compressor crankcase heaters which should be energized at least 24 hours prior to cooling operation to clear any liquid refrigerant from the compressors
CAUTION
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units All motors to include and not be limited to pump motors and condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection
CAUTION
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
16
The standard compressors must be on a
minimum of 5 minutes and off for a
minimum of 5 minutes The cycle rate must
be no more than 6 starts per hour
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 minutes The cycle rate must
be no more than 6 starts per hour
The compressor life will be seriously
shortened by reduced lubrication and the
pumping of excessive amounts of liquid oil
and liquid refrigerant
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is laminated
in plastic and located inside the control
compartment door
General Maintenance
When the initial startup is made and on a
periodic schedule during operation it is
necessary to perform routine service checks
on the performance of the condensing unit
This includes reading and recording suction
pressures and checking for normal sub-
cooling and superheat
COMPRESSOR ROTATION
Scroll compressors are directional and will be damaged by operation in the wrong direction Low pressure switches on compressors have been disconnected after factory testing Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
CAUTION
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
17
Installation
Forklifting the Unit
CF Series condensing unit sizes 2-25 amp 30
tons can be lifted using a forklift 2-7 ton
units must have forks at least 48rdquo in length
9-25 amp 30 ton units must have forks 72rdquo in
length or the forks must have 72rdquo fork
extensions Standard units can be lifted from
all sides except the condenser coil side CF
Series condensing unit sizes 26 amp 31-70
tons cannot be lifted using a forklift They
can be lifted as shown in Figure 3
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6rdquo away from the
edge of the unit
Figure 1 - Forklifting a CF Series A Cabinet
Figure 2 - Forklifting a CF Series B and C
Cabinet
FORKLIFTING 2-7 TON UNITS
Forks or Fork Extensions must be at least 48rdquo in length
CAUTION
FORKLIFTING 9-25 amp 30 TON UNITS
Forks or Fork Extensions must be at least 72rdquo in length
CAUTION
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
18
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length Minimum
cable length is 99rdquo for CF Series 9-70 ton
units CF Series 2-7 ton units do not include
factory installed lifting lugs and should be
lifted by forklift only Care should be taken
to prevent damage to the cabinet coils and
condenser fans
Before lifting unit be sure that all shipping
material has been removed from unit Secure
hooks and cables at all lifting points lugs
provided on the unit
Figure 3 ndash Lifting Details and Orientation of
a CF Series 9-70 ton Condensing Unit
Locating the Unit
The CF Series condenser and condensing
unit is designed for outdoor applications and
mounting at ground level or on a rooftop It
must be placed on a level and solid
foundation that has been prepared to support
its weight When installed at ground level a
one-piece concrete slab should be used with
footings that extend below the frost line
Also with ground level installation care
must be taken to protect the coil fins from
damage due to vandalism or other causes
The first clearance table below gives the
clearance values for proper unit operation
The second clearance table gives the
clearance necessary for removing the coil
without disassembling a large part of the
condensing unit For ease of removing the
condenser coil use the second table
clearances for the right hand side of the unit
Table 1 ndashClearances for Proper Operation
Location Unit Size
2-7 tons 9-70 tons
Front -
(Controls
Side)
Unobstructed 36rdquo
Left Side 6rdquo 30rdquo
Right Side 6rdquo 36rdquo
Top 3rdquo Unobstructed
Back 18rdquo 6rdquo
Table 2 ndash Clearances for Coil Pull
Unit Size Right Hand Side
2-7 tons 42rdquo
9-15 tons 42rdquo
16-25 amp 30 tons 54rdquo
26 amp 31-70 tons 66rdquo
Figure 4 - Orientation of Series 2-7 ton
Condensing Unit
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
19
The placement relative to the building air
intakes and other structures must be
carefully selected Airflow to and from the
condenser or condensing unit must not be
restricted to prevent a decrease in
performance and efficiency
The installation position for 9-70 ton units
must provide at least 30rdquo of left and right
side clearance for proper airflow to the
condenser coils When units are mounted
adjacent to each other the minimum right
and left side clearance required between the
units is 60rdquo or 5 feet Similarly when 2-7
ton units are mounted adjacent to each other
the minimum clearance required between
the back side of the units is 36rdquo or 3 feet
Units should not be installed in an enclosure
or pit that is deeper than the height of the
unit When recessed installation is
necessary the clearance to maintain proper
airflow is at least 5 feet (3 feet for 2-7tons)
CF Series condensers and condensing units
that have a vertical air discharge must have
no obstruction above the equipment Do not
place the unit under an overhang CF Series
condensers and condensing units that have a
horizontal discharge must have no
obstruction in front of the unit
For proper unit operation the immediate
area around condenser must remain free of
debris that may be drawn in and obstruct
airflow in the condensing section
Consideration must be given to obstruction
caused by snow accumulation when placing
the unit
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor vibration
isolators may be used
Access Doors
Access doors are provided to the compressor
and electrical compartment
Low Ambient Operation
During low ambient temperatures the vapor
refrigerant will migrate to the cold part of
the system and condense into liquid All CF
Series compressors are provided with
factory installed crankcase heaters to help
prevent liquid refrigerant from slugging the
compressors during startup in low ambient
conditions The condenser or condensing
unit must have continuous power 24 hours
prior to startup This ensures the compressor
will receive sufficient refrigerant vapor at
startup Standard units can operate down to
55degF ambient temperature
AAON head pressure control units can
operate down to 35degF ambient temperature
Three different head pressure control
options available are adjustable fan cycling
ECM condenser fan or VFD controlled
condenser fans See detailed information
following
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
PVC PIPING
PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals Polyolester (POE) oils used with R-410A and other refrigerants even in trace amounts in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure
CAUTION
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
20
system down to 0degF outside air temperature
See detailed information following
Fan Cycling Low Ambient
Adjustable fan cycling is a low ambient
head pressure control option that cycles the
condenser fans to maintain refrigerant
circuit head pressures at acceptable levels
during cooling operation The head pressure
set point (100-470 psi) and pressure
differential (35-200 psi) can be field
adjusted using a flathead screwdriver For
example if the head pressure is set to
300psi and the differential is set to 100psi
then fans will cut in at 300psi and cut out at
200psi Fan cycling and variable speed
condenser fan head pressure control options
allow mechanical cooling with ambient
temperatures down to 35degF
Figure 5 - Adjustable Fan Cycling Switch
Variable Speed Low Ambient
Variable speed condenser fan head pressure
control is a low ambient head pressure
control option that sends a variable signal in
relation to the refrigerant circuit head
pressure of the system to an electronically
commutated motor or VFD The motor
either speeds up or slows down air flow
accordingly in order to maintain constant
head pressure Fan cycling and variable
speed condenser fan head pressure control
options allow mechanical cooling with
ambient temperatures down to 35degF
Flooded Condenser Low Ambient
Flooded condenser low ambient control
maintains normal head pressure during
periods of low ambient When the ambient
temperature drops the condensing
temperature and therefore pressure drops
Without ambient control the system would
shut down on low discharge pressure The
flooded condenser method of low ambient
control fills the condenser coil with liquid
refrigerant decreasing the heat transfer
capacity of the coil which allows the coil to
operate at an acceptable discharge pressure
The condenser coil will not be flooded
during summer ambient temperatures so a
receiver is included to store the additional
liquid refrigerant required to flood the
condenser coil in low ambient
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver and at the same time
bypassing hot gas around the condenser to
the inlet of the receiver This reduces liquid
refrigerant flow from the condenser
reducing its effective surface area which in
turn increases the condensing pressure At
the same time the bypassed hot gas raises
liquid pressure in the receiver allowing the
system to operate properly CF Series
condensers and condensing units use an
LAC valve for low ambient operation
LAC Valve
The Low Ambient Control (LAC) valve is a
non-adjustable three way valve that
modulates to maintain receiver pressure As
the receiver pressure drops below the valve
setting (295 psig for R-410A) the valve
modulates to bypass discharge gas around
the condenser The discharge gas warms the
liquid in the receiver and raises the pressure
to the valve setting The following
schematic shows an example system using
the LAC valve
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
21
Figure 6 - Piping Schematic of Example System using the LAC Valve
Condenser Flooding
In order to maintain head pressure in the
refrigeration system liquid refrigerant is
kept in the condenser coil to reduce
condenser coil surface The following chart
shows the percentage that a condenser coil
must be flooded in order to function
properly at the given ambient temperature
During higher ambient temperatures the
entire condenser coil is required to condense
refrigerant During these higher ambient
temperatures a receiver tank is used to
contain the refrigerant that was required to
flood the condenser during low ambient
operation The receiver is factory-sized to
contain all of the flooded volume Without a
receiver there would be high head pressures
during higher ambient conditions
Table 3 - Condenser Flooding PERCENTAGE OF CONDENSER TO BE
FLOODED
Ambient
Temperature
(degF)
Evaporating Temperature (degF)
0deg 10deg 20deg 30deg 35deg 40deg 45deg 50deg
70deg 40 24 0 0 0 0 0 0
60deg 60 47 33 17 26 20 10 4
50deg 70 60 50 38 45 40 33 28
40deg 76 68 60 50 56 52 46 42
30deg 80 73 66 59 64 60 55 51
20deg 86 77 72 65 69 66 62 59
0deg 87 83 78 73 76 73 70 68
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
22
Refrigerant Piping
(See back of the manual for refrigerant
piping diagrams)
General
Piping from the condensing unit to the air
handler is the responsibility of the installing
contractor
Use only clean type ldquoACRrdquo copper tubing
that has been joined with high temperature
brazing alloy
The pipe or line sizes must be selected to
meet the actual installation conditions and
NOT simply based on the connection sizes
at the condensing unit or air handler
All CF Series condensing units are provided
with in-line shutoff valves on both the liquid
and suction lines These should remain
closed until the system is ready for start-up
after installation
Piping should conform to generally accepted
practices and codes
Care must be taken not to cross the circuits
on multiple circuit systems
Upon completion of piping connection the
interconnecting piping and air handler
MUST BE evacuated to 500 microns or less
leak checked and charged with refrigerant
Determining Refrigerant Line Size
The piping between the condenser and low
side must ensure
1 Minimum pressure drop and
2 Continuous oil return and
3 Prevention of liquid refrigerant slugging
or carryover
Minimizing the refrigerant line size is
favorable from an economic perspective
reducing installation costs and reducing the
potential for leakage However as pipe
diameters decrease pressure drop increases
Excessive suction line pressure drop causes
loss of compressor capacity and increased
power usage resulting in reduced system
efficiency Excessive pressure drops in the
liquid line can cause the liquid refrigerant to
flash resulting in faulty TXV operation and
improper system performance In order to
operate efficiently and cost effectively
while avoiding malfunction refrigeration
systems must be designed to minimize both
cost and pressure loss
REFRIGERANT PIPING
Line sizes must be selected to meet actual installation conditions not simply based on the connection sizes at the condensing unit or air handling unit
CAUTION
REFRIGERANT PIPING
This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping between the condenser or condensing unit and the air handling unit AAON Inc is not responsible for interconnecting refrigerant piping Consult ASHRAE Handbook ndash Refrigeration and ASME Standards
CAUTION
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
23
Equivalent Line Length
All line lengths discussed in this manual
unless specifically stated otherwise are
Equivalent Line Lengths The frictional
pressure drop through valves fittings and
accessories is determined by establishing the
equivalent length of straight pipe of the
same diameter Always use equivalent line
lengths when calculating pressure drop
Special piping provisions must be taken
when lines are up vertical risers or in
excessively long line runs AAON does not
recommend running underground
refrigerant lines
Liquid Line
When sizing the liquid line it is important to
minimize the refrigerant charge to reduce
installation costs and improve system
reliability This can be achieved by
minimizing the liquid line diameter
However reducing the pipe diameter will
increase the velocity of the liquid refrigerant
which increases the frictional pressure drop
in the liquid line and causes other
undesirable effects such as noise
Maintaining the pressure in the liquid line is
critical to ensuring sufficient saturation
temperature avoiding flashing upstream of
the TXV and maintaining system
efficiency Pressure losses through the
liquid line due to frictional contact installed
accessories and vertical risers are
inevitable Maintaining adequate sub-
cooling at the condenser to overcome these
losses is the only method to ensure that
liquid refrigerant reaches the TXV
Liquid refrigerant traveling upwards in a
riser loses head pressure If the evaporator is
below the condenser with the liquid line
flowing down the gravitational force will
increase the pressure of the liquid
refrigerant This will allow the refrigerant to
withstand greater frictional losses without
the occurrence of flashing prior to the TXV
A moisture-indicating sight glass may be
field installed in the liquid line to indicate
the occurrence of premature flashing or
moisture in the line The sight glass should
not be used to determine if the system is
properly charged Use temperature and
pressure measurements to determine
liquid sub-cooling not the sight glass
Liquid Line Routing
Care should be taken with vertical risers
When the system is shut down gravity will
pull liquid down the vertical column and
back to the condenser when it is below the
evaporator This could potentially result in
compressor flooding A check valve can be
installed in the liquid line where the liquid
column rises above the condenser to prevent
this The liquid line is typically pitched
along with the suction line or hot gas line
to minimize the complexity of the
configuration
Liquid Line Insulation
When the liquid line is routed through
regions where temperature losses are
expected no insulation is required as this
may provide additional sub-cooling to the
refrigerant When routing the liquid line
through high temperature areas insulation of
the line is appropriate to avoid loss of sub-
cooling through heat gain
Liquid Line Guidelines
In order to ensure liquid at the TXV the
sum of frictional losses and pressure loss
due to vertical rise must not exceed
available sub-cooling A commonly used
guideline to consider is a system design with
pressure losses due to friction through the
line not to exceed a corresponding 1-2degF
change in saturation temperature An
additional recommendation is that the sum
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
24
of frictional losses (including valve losses
filter drier losses other accessories and line
losses) and pressure loss due to vertical rise
should not exceed 8degF
If the velocity of refrigerant in the liquid line
is too great it could cause excessive noise or
piping erosion The recommended
maximum velocities for liquid lines are
100 fpm from the condenser to a receiver
tank to discourage fluid backup and
300 fpm from receiver tank to the
evaporator to minimize valve induced liquid
hammer
Liquid Line Accessories
Liquid line shut off valves and filter driers
are factory provided The total length
equivalent of pressure losses through valves
elbows and fittings must be considered when
adding additional components in the field It
is a good practice to utilize the fewest
elbows that will allow the mating units to be
successfully joined
A liquid line receiver is factory installed on
units with modulating hot gas reheat units
with low ambient control flooded condenser
and units with heat pump
A normally closed solenoid valve is
recommended on liquid lines over 100 ft in
length to prevent oil migration when the
compressors are off The solenoid needs to
be wired so that it is open when the
compressors turn on and closed when the
compressors turn off It can be wired to the
compressor contactor coil and installed near
the outdoor unit
Suction Line
The suction line is more critical than the
liquid line from a design and construction
standpoint More care must be taken to
ensure that adequate velocity is achieved to
return oil to the compressor at minimum
loading conditions However reducing the
piping diameter to increase the velocity at
minimal load can result in excessive
pressure losses capacity reduction and
noise at full load
Suction Line Routing
Pitch the suction line in the direction of flow
(about 1 foot per 120 feet of length) to
maintain oil flow towards the compressor
and keep it from flooding back into the
evaporator Crankcase heaters are provided
to keep any condensed refrigerant that
collects in the compressor from causing
damage or wear Make sure to provide
support to maintain suction line positioning
and insulate completely between the
evaporator and condensing unit
It is important to consider part load
operation when sizing suction lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double suction riser can be applied to the
situation of part load operation with a
suction riser A double suction riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double suction riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
25
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load
Figure 7 - Double Suction Riser
Construction
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams (See
Figure 8 amp Figure 9) the cooling mode will
use both lines and the heating mode will use
only one
Suction Line Traps
Include a trap immediately after the
evaporator coil outlet to protect the TXV
bulb from liquid refrigerant
Include traps every 10 feet in vertical riser
sections
Suction Line Insulation
The entire suction line should be insulated
with a minimum 1 inch thick Armaflex
insulation This prevents condensation from
forming on the line and reduces any
potential loss in capacity associated with
heat gain placing additional load on the
system
Suction Line Guidelines
For proper performance suction line
velocities less than a 4000 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 1000 fpm minimum may be applied
When suction flow is up variable capacity
compressors require a minimum velocity of
1500 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When suction flow
is up and the tandem has a variable capacity
compressor the partial load velocities must
be greater than 1500 fpm and greater than
the minimum velocity required to return oil
for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the liquid line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
26
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Suction Line Accessories
If the job requirements specify suction
accumulators they must be separately
purchased and field installed Heat pump
units will include a factory installed suction
accumulator
Discharge Line
The discharge line is similar to the suction
line from a design and construction
standpoint Care must be taken to ensure that
adequate velocity is achieved to return oil to
the compressor at minimum loading
conditions However reducing the piping
diameter to increase the velocity at minimal
load can result in excessive pressure losses
capacity reduction and noise at full load
Pressure loss in the discharge line has less of
an impact on capacity than pressure loss in
the suction line Pressure loss in the
discharge line causes the compressors to
work harder and thus use more power
Discharge Line Routing
In a heat pump system the field installed
suction line is also used as a discharge line
in the heating mode of operation so the line
must be sized to meet both the suction line
conditions in cooling mode and the
discharge line conditions in heating mode
Because it is used in both directions for a
heat pump unit the line should be installed
level not pitched to facilitate oil return in
both modes of operation
It is important to consider part load
operation when sizing discharge lines At
minimum capacity refrigerant velocity may
not be adequate to return oil up the vertical
riser Decreasing the diameter of the vertical
riser will increase the velocity but also the
frictional loss
For difficult line routing applications a
double discharge riser can be applied to the
situation of part load operation with a
discharge riser A double discharge riser is
designed to return oil at minimum load
while not incurring excessive frictional
losses at full load A double discharge riser
consists of a small diameter riser in parallel
with a larger diameter riser and a trap at the
base of the large riser At minimum
capacity refrigerant velocity is not sufficient
to carry oil up both risers and it collects in
the trap effectively closing off the larger
diameter riser and diverting refrigerant up
the small riser where velocity of the
refrigerant is sufficient to maintain oil flow
At full load the mass flow clears the trap of
oil and refrigerant is carried through both
risers The smaller diameter pipe should be
sized to return oil at minimum load while
the larger diameter pipe should be sized so
that flow through both pipes provides
acceptable pressure drop at full load (See
the Double Suction Riser Construction
Figure 7)
A double riser can also be used for heat
pump operation The specific volume
(ft3lb) of refrigerant at the discharge
temperature and pressure (heating mode line
conditions) is significantly lower than the
specific volume at the suction temperature
and pressure (cooling mode line conditions)
SUCTION RISER TRAPS
Circuits require suction riser traps every 10 feet
CAUTION
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
27
To compound the issue the capacity in
heating mode is lower than the capacity in
cooling mode The discharge velocity in the
riser during heating mode is much lower
than the suction velocity during cooling
mode Often a double riser is necessary to
get acceptable velocities for the discharge
mode and acceptable velocities for the
suction mode In the example diagrams the
cooling mode will use both lines and the
heating mode will use only one See the
following schematics that illustrate how the
double discharge riser can work for heat
pump applications
Figure 8 ndash Heat Pump Piping Schematic of
Suction Vapor Flow Down in Double Riser
Discharge Line Traps
Include traps every 10 feet in vertical riser
sections
Discharge Line Insulation
Although a typical discharge line does not
need to be insulated the suction line does
Since the same line is used for both the line
must be insulated as described in the Suction
Line Insulation section
Figure 9 ndash Heat Pump Piping Schematic of
Discharge Vapor Flow Up in Double Riser
Discharge Line Guidelines
For proper performance discharge line
velocities less than a 3500 fpm maximum
are recommended The minimum velocity
required to return oil is dependent on the
pipe diameter however a general guideline
of 900 fpm minimum may be applied
When discharge flow is up variable
capacity compressors require a minimum
velocity of 900 fpm at full load
Tandem compressors must be considered for
full load operation (both compressors
operating) and at partial load (only one
compressor operating) When discharge
flow is up and the tandem has a variable
capacity compressor the partial load
velocities must be greater than 900 fpm and
greater than the minimum velocity required
to return oil for onoff compressors
Heat pump vapor lines must be checked for
suction flow (cooling mode operation) and
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
28
discharge flow (heating mode operation)
The same line must be used for both modes
of operation
In a fashion similar to the suction line a
common guideline to consider is a system
design with pressure losses due to friction
through the line not to exceed a
corresponding 1-2degF change in saturation
temperature
For split system piping with long horizontal
runs and short vertical risers a smaller pipe
size can be used to provide sufficient
velocity to return oil in vertical risers at part
loads and a larger size pipe can be used on
the horizontal runs and vertical drop
sections This helps with oil return yet
keeps the pressure drop to a minimum
Hot Gas Bypass Line
Hot Gas Bypass is available for use with DX
systems that may experience low suction
pressure during the operating cycle This
may be due to varying load conditions
associated with VAV applications or units
supplying a large percentage of outside air
The system is designed to divert refrigerant
from the compressor discharge to the low
pressure side of the system in order to keep
the evaporator from freezing and to maintain
adequate refrigerant velocity for oil return at
minimum load
Hot discharge gas is redirected to the
evaporator inlet via an auxiliary side
connector (ASC) to false load the evaporator
when reduced suction pressure is sensed
Field piping between the condensing unit
and the evaporator is required
Hot Gas Bypass Piping Considerations
Pitch the hot gas bypass (HGB) line
downward in the direction of refrigerant
flow toward the evaporator
When installing vertical hot gas bypass
lines an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Install a sight glass in
the oil drip line for observation Run an oil
return line using 18 inch capillary tube 10
feet in length from the hot gas bypass line
oil drip line to the suction line Connect the
oil return line below the sight glass and
1 inch above the bottom of the oil drip line
Figure 10 ndash Oil Return Line
HGB valves are adjustable Factory HGB
valve settings will be sufficient for most
applications but may require slight
adjustments for some applications including
some make up air applications
Insulate the entire length of the HGB line
with a minimum 1 inch thick Armaflex
insulation
DISCHARGE RISER TRAPS
Circuits require discharge riser traps every 10 feet
CAUTION
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
29
Hot Gas Bypass Line Guidelines
Choose a small size line to ensure oil return
and minimize refrigerant charge
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline to use is approximately 900 fpm
Hot Gas Reheat
The AAON modulating hot gas reheat
system diverts hot discharge gas from the
condenser to the air handling unit through
the hot gas line Field piping between the
condensing unit and the air handler is
required
The line delivers the hot discharge gas to the
reheat coil andor the hot gas bypass valve
so it is sized as a discharge line
Discharge lines should be sized to ensure
adequate velocity of refrigerant to ensure oil
return avoid excessive noise associated with
velocities that are too high and to minimize
efficiency losses associated with friction
Pitch the hot gas line in the direction of flow
for oil return
When installing vertical hot gas reheat lines
an oil drip line must be provided at the
lowest point in the system The oil drip line
must be vertical its diameter should be the
same as the diameter of the riser and it
should be 1 foot long Run an oil return line
using 18 inch capillary tube 10 feet in
length from the hot gas reheat line oil drip
line to the suction line Connect the oil
return line below the sight glass and 1 inch
above the bottom of the oil drip line (See
Oil Return Line Figure 10)
Insulate the entire length of the hot gas line
with a minimum 1 inch thick Armaflex
insulation
Hot Gas Reheat Guidelines
Maintain velocities below a maximum of
3500 fpm A general minimum velocity
guideline is 900 fpm
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
30
Electrical
The single point electrical power connections
are made in the electrical control
compartment
Verify the unit nameplate voltage agrees with
the power supply Connect power and control
field wiring as shown on the unit specific
wiring diagram provided with the unit
NOTE Units are factory wired for 208V
230V 460V or 575V In some units the
208V and 230V options may also be provided
in single or three phase configurations The
transformer configuration must be checked by
a qualified technician prior to startup
Size supply conductors based on the unit
MCA rating Supply conductors must be rated
a minimum of 167degF (75degC)
Route power and control wiring separately
through the utility entry Do not run power
and signal wires in the same conduit
Protect the branch circuit in accordance with
code requirements The unit must be
electrically grounded in accordance with local
codes or in the absence of local codes the
current National Electric Code ANSINFPA
70 or the current Canadian Electrical Code
CSA C221
Power wiring is to the unit terminal block or
main disconnect All wiring beyond this point
has been done by the manufacturer and cannot
be modified without affecting the units
agencysafety certification
Three phase voltage imbalance will cause
motor overheating and premature failure The
maximum allowable imbalance is 5
Voltage imbalance is defined as 100 times the
maximum deviation from the average voltage
divided by the average voltage
Example
(218V+237V+235V)3 = 230V then
100(230V-218V)230V = 52 which
exceeds the allowable imbalance
Check voltage imbalance at the unit
disconnect switch and at the compressor
terminal Contact your local power company
for line voltage corrections
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Before attempting to perform any installation service or maintenance shut off all electrical power to the unit at the disconnect switches Unit may have multiple power supplies Failure to disconnect power could result in dangerous operation serious injury death or property damage
WARNING
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
31
NOTE Startup technician must check for
proper motor rotation and check fan motor
amperage listed on the motor nameplate is not
exceeded Motor overload protection may be
a function of the variable frequency drive and
must not be bypassed
Wire control signals to the unitrsquos low voltage
terminal block located in the controls
compartment
If any factory installed wiring must be
replaced use a minimum 221degF (105degC) type
AWM insulated conductors
SEALING ELECTRICAL ENTRIES
Installing Contractor is responsible for proper sealing of the electrical entries into the unit Failure to seal the entries may result in damage to the unit and property
CAUTION
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
32
Startup (See back of the manual for startup form)
Before startup of the condenser or condensing
unit make sure that the following items have
been checked
1 Verify that electrical power is available to
the unit
2 Verify that any remote stopstart device
connected to the unit controller is
requesting the unit to start
Cycle through all the compressors to confirm
that all are operating within tolerance
While performing the check use the startup
form to record observations of amps and
refrigerant pressures
When all is running properly place the
controller in the Run mode and observe the
system until it reaches a steady state of
operation
Compressor Operation
The compressors must be off for a minimum
of 5 minutes and on for a minimum of 5
minutes Short cycling of the compressors can
cause undue stress and wear
3-PHASE ROTATION
Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units Condenser fan motors should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection Variable frequency drives are programmed to automatically rotate the fan in the correct rotation Do not rely on fans with variable frequency drives for compressor rotation
CAUTION
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
QUALIFIED INSTALLER
Improper installation adjustment alteration service or maintenance can cause property damage personal injury or loss of life Startup and service must be performed by a Factory Trained Service Technician
WARNING
Before completing installation a complete operating cycle should be observed to verify that all components are functioning properly
CAUTION
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
33
Variable Capacity Compressor Controller
Units with variable capacity scroll
compressors may include a variable capacity
compressor controller The following is an
explanation of the terminals and
troubleshooting of the alert flash codes on the
controller For more information on the
compressor controller see Emerson Climate
Bulletin AE8-1328
Figure 11 - Variable Capacity Compressor
Controller
Low Voltage Terminals
24COM Module Common
24VAC Module Power
C1 Demand Input -
C2 Demand Input +
P1 Pressure Common
P2 Pressure Input
P3 Pressure Power 5VDC
P4 Pressure Shield
P5 Pressure Output -
P6 Pressure Output +
T1 amp T2 Discharge Temperature Sensor
High Voltage Terminals
A1 amp A2 Alarm Relay Out
M1 amp M2 Contactor
L1 Control Voltage N
L2 Control Voltage L
U1 amp U2 Variable Capacity Unloader Solenoid
V1 amp V2 Vapor Injection Solenoid
The compressor controller modulates the
compressor unloader solenoid in an onoff
pattern according the capacity demand signal
of the system The following table shows the
linear relationship between the demand signal
and compressor capacity modulation The
compressor controller also protects the
compressor against high discharge
temperature Refer to Table 5 for the
relationship between thermistor temperature
readings and resistance values
COMPRESSOR CONTROLLER
To avoid damaging the compressor controller DO NOT connect wires to terminals C3 C4 T3 T4 T5 or T6
WARNING
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes
5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes The cycle rate must not exceed 6 starts per hour
WARNING
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
34
Table 4 - Demand Signal vs Compressor Capacity Modulation
Figure 12 - Compressor Controller Flash Code Details
Demand
Signal (VDC) Loaded Unloaded Time Loaded
Time
Unloaded
Compressor
Capacity
100 Off Off Off Off 0
144 10 90 15 sec 135 sec 10
300 50 50 75 sec 75 sec 50
420 80 20 12 sec 3 sec 80
500 100 0 15 sec 0 sec 100
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
35
Table 5 - Thermistor Temperature vs Resistance Values
degC degF kΩ degC degF kΩ
-40 -40 288960 75 167 1273
-35 -31 208722 80 176 1079
-30 -22 152220 85 185 920
-25 -13 112144 90 194 787
-20 -4 83472 95 203 677
-15 5 62728 100 212 585
-10 14 47574 105 221 509
-5 23 36399 110 230 445
0 32 28082 115 239 387
5 41 21841 120 248 335
10 50 17117 125 257 292
15 59 13514 130 266 258
20 68 10744 135 275 228
25 77 8600 140 284 202
30 86 6928 145 293 180
35 95 5616 150 302 159
40 104 4581 155 311 139
45 113 3758 160 320 125
50 122 3099 165 329 112
55 131 2568 170 338 101
60 140 2140 175 347 092
65 149 1791 180 356 083
70 158 1507
Compressor Lockouts
Some units include adjustable compressor
lockouts The compressor lockout in the
picture below can be set to any temperature
between -10degF and 70degF The ambient
temperature sensor hangs right outside the
unit with a cover
Figure 13 - Adjustable compressor lockout
Heat pump units include a non-adjustable
compressor lockout for the cooling mode set
to 55degF and an adjustable compressor
lockout for the heating mode that can be set
between 20degF to 95degF If a heat pump is
selected with the compressor lockout
feature the adjustable compressor lockout
will change to the -10degF to 70degF range
Figure 14 - Ambient sensor cover
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
36
Maintenance
General
Qualified technicians must perform routine
service checks and maintenance This
includes reading and recording the
condensing and suction pressures and
checking for normal sub-cooling and
superheat
Compressors
The scroll compressors are fully hermetic
and require no maintenance except keeping
the shell clean
Refrigerant Filter Driers
Each refrigerant circuit contains a filter
drier Replacement is recommended when
there is excessive pressure drop across the
assembly or moisture is indicated in a liquid
line sight glass
Table 6 - Max Filter Drier Pressure Drops
Circuit Loading Max Pressure Drop
100 10 psig
50 5 psig
Adjusting Refrigerant Charge
All AAON CF Series condensers and
condensing units are shipped with a factory
holding charge The factory charge is
different depending on the unit size and
system (heat pump modulating hot gas
reheat LAC) The factory charge per circuit
is shown on the unit nameplate Adjusting
the charge of the system will be required
during installation
Adjusting the charge of a system in the field
must be based on determination of liquid
sub-cooling and evaporator superheat On a
system with a thermostatic expansion valve
liquid sub-cooling is more representative of
the charge than evaporator superheat but
both measurements must be taken
Before Charging
Refer to the Unit Nameplate to determine
which refrigerant must be used to charge the
system
Unit being charged must be at or near full
load conditions before adjusting the charge
Units equipped with hot gas bypass must
have the hot gas bypass valve closed to get
the proper charge
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while
the unit is in cooling mode After charging
unit should be operated in reheat
(dehumidification) mode to check for
correct operation
Units equipped with heat pump options
should be charged in heating mode to get the
COMPRESSOR LUBRICANT
Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems Refer to the compressor label for the proper compressor lubricant type
CAUTION
CLEAN AIR ACT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCrsquos and HCFCrsquos) as of July 1 1992 Approved methods of recovery recycling or reclaiming must be followed Fines andor incarceration may be levied for non-compliance
CAUTION
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
37
proper charge After charging unit should
be operated in cooling mode to check for
correct charge Charge may need to be
adjusted for cooling mode If adjustments
are made in the cooling mode heating mode
must be rerun to verify proper operation
After adding or removing charge the system
must be allowed to stabilize typically 10-15
minutes before making any other
adjustments
The type of unit and options determine the
ranges for liquid sub-cooling and evaporator
superheat Refer to Table 7 when
determining the proper sub-cooling
For units equipped with low ambient (0degF)
option see the special charging instructions
at the end of this section
Checking Liquid Sub-cooling
Measure the temperature of the liquid line as
it leaves the condenser coil
Read the gauge pressure at the liquid line
close to the point where the temperature was
taken You must use liquid line pressure as it
will vary from discharge pressure due to
condenser coil pressure drop
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the measured liquid line
temperature from the saturated temperature
to determine the liquid sub-cooling
Compare calculated sub-cooling to the table
below for the appropriate unit type and
options
Checking Evaporator Superheat
Measure the temperature of the suction line
close to the compressor
Read gauge pressure at the suction line close
to the compressor
Convert the pressure obtained to a saturated
temperature using the appropriate refrigerant
temperature-pressure chart
Subtract the saturated temperature from the
measured suction line temperature to
determine the evaporator superheat
For refrigeration systems with tandem
compressors it is critical that the suction
superheat setpoint on the TXV is set with
one compressor running The suction
superheat should be 10-13degF with one
compressor running The suction superheat
will increase with both compressors in a
tandem running Inadequate suction
superheat can allow liquid refrigerant to
return to the compressors which will wash
the oil out of the compressor Lack of oil
lubrication will destroy a compressor
Liquid sub-cooling should be measured with
both compressors in a refrigeration system
running
Compare calculated superheat to Table 7 for
the appropriate unit type and options
Table 7 - Acceptable Refrigeration Circuit
Values
Air-Cooled CondAir-Source Heat Pump
Sub-Cooling
8-15degF 2-4degF (HP)
Sub-Cooling with
Hot Gas Reheat 8-15degF 2-6degF (HP)
Superheat
8-15degF
In cooling mode operation
Sub-cooling must be increased by 2degF per
20 feet of vertical liquid line rise for R-410A
Superheat will increase with long
suction line runs
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
38
Adjusting Sub-cooling and Superheat
Temperatures
The system is overcharged if the sub-cooling
temperature is too high and the evaporator is
fully loaded (low loads on the evaporator
result in increased sub-cooling) and the
evaporator superheat is within the
temperature range as shown in Table 7 (high
superheat results in increased sub-cooling)
Correct an overcharged system by reducing
the amount of refrigerant in the system to
lower the sub-cooling
The system is undercharged if the superheat
is too high and the sub-cooling is too low
Correct an undercharged system by adding
refrigerant to the system to reduce superheat
and raise sub-cooling
If the sub-cooling is correct and the
superheat is too high the TXV may need
adjustment to correct the superheat
Special Low Ambient Option Charging
Instructions
For units equipped with low ambient control
(LAC) refrigerant flood back option being
charged when the ambient temperature is
warm
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
must be added Add approximately 80 of
the receiver tank volume to the charge to
help fill the receiver tank The additional
charge is required for the system when
running in cold ambient conditions
For units equipped with low ambient
refrigerant flood back option being charged
when the ambient temperature is cold
Once enough charge has been added to get
the evaporator superheat and sub-cooling
values to the correct setting more charge
may need to be added If the ambient
temperature is 0degF no more charge is
required If the ambient temperature is
around 40degF add approximately 40 of the
receiver tank volume
The unit will have to be checked for proper
operation once the ambient temperature is
above 80degF
EXPANSION VALVE ADJUSTMENT
Thermal expansion valves must be adjusted to approximately 8-15degF of suction superheat Failure to have sufficient superheat will damage the compressor and void the warranty
CAUTION
DO NOT OVERCHARGE Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure
CAUTION
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
39
Oil Level
It is critical that the refrigerant line piping is
designed to maintain proper oil return to the
compressors Some systems may require oil
to be added in addition to what is provided
in the compressors The oil is a PVE type
and is available from your AAON
Representative under part number V41850
Proper oil level should be observed under
minimum load conditions On units
equipped with tandem compressors all oil is
returned to the lead compressor in each
tandem pair When only the lead
compressor is running the oil level should
be a minimum of ⅜ from the bottom of the
sight glass With both compressors running
the level in the lead compressor should drop
to the bottom of the sight glass and the level
in the second compressor should be a
minimum of ⅜ from the bottom of its sight
glass
Table 8 - R-410A Refrigerant Temperature-Pressure Chart
degF PSIG degF PSIG degF PSIG degF PSIG degF PSIG
20 783 47 1347 74 2137 101 3210 128 4632
21 800 48 1372 75 2171 102 3256 129 4693
22 818 49 1397 76 2206 103 3302 130 4754
23 836 50 1422 77 2241 104 3349 131 4816
24 854 51 1448 78 2277 105 3396 132 4878
25 872 52 1474 79 2313 106 3444 133 4941
26 891 53 1501 80 2349 107 3493 134 5005
27 910 54 1528 81 2386 108 3542 135 5069
28 929 55 1555 82 2423 109 3591 136 5134
29 949 56 1582 83 2460 110 3641 137 5200
30 968 57 1610 84 2498 111 3691 138 5266
31 988 58 1638 85 2537 112 3742 139 5333
32 1009 59 1667 86 2575 113 3794 140 5401
33 1029 60 1696 87 2614 114 3846 141 5470
34 1050 61 1725 88 2654 115 3899 142 5539
35 1071 62 1754 89 2694 116 3952 143 5609
36 1092 63 1784 90 2735 117 4005 144 5679
37 1114 64 1815 91 2776 118 4059 145 5751
38 1136 65 1845 92 2817 119 4114 146 5823
39 1158 66 1876 93 2859 120 4169 147 5896
40 1181 67 1907 94 2901 121 4225 148 5969
41 1203 68 1939 95 2944 122 4282 149 6044
42 1227 69 1971 96 2987 123 4339 150 6119
43 1250 70 2004 97 3030 124 4396
44 1274 71 2036 98 3075 125 4454
45 1298 72 2070 99 3119 126 4513
46 1322 73 2103 100 3164 127 4573
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
40
Lubrication
All original motors and bearings are
furnished with an original factory charge of
lubrication Certain applications require
bearings be re-lubricated periodically The
schedule will vary depending on operating
duty temperature variations or severe
atmospheric conditions
Bearings should be re-lubricated at normal
operating temperatures but not when
running
Condenser Tube Inspection
The coils are leak tested at 650 psig before
shipment AAON will not be responsible for
loss of refrigerant It is the responsibility of
the installer to verify that the system is
sealed before charging with refrigerant
Maintenance Recommendations
Fan Motor Maintenance
Cleaning - Remove oil dust water and
chemicals from exterior of motor Keep
motor air inlet and outlet open Blow out
interior of open motors with clean
compressed air at low pressure
Labeled Motors - It is imperative for repair
of a motor with Underwritersrsquo Laboratories
label that original clearances be held that all
plugs screws other hardware be fastened
securely and that parts replacements be
exact duplicates or approved equals
Violation of any of the above invalidates
Underwritersrsquo Label
Access Doors
If scale deposits or water is found around the
access doors adjust door for tightness
Adjust as necessary until leaking stops when
door is closed
Propeller Fans and Motors
The fans are directly mounted on the motor
shafts and the assemblies require minimal
maintenance except to assure they are clear
of dirt or debris that would impede the
airflow
Recommended Annual Inspection
In addition to the above maintenance
activities a general inspection of the unit
surface should be completed at least once a
year
Air-Cooled Condenser
The air-cooled condenser section rejects
heat by passing outdoor air over the fin tube
coils for cooling of the hot refrigerant gas
from the compressors
The condenser coils should be inspected
annually to ensure unrestricted airflow If
the installation has a large amount of
airborne dust or other material the
condenser coils should be cleaned with a
water spray in a direction opposite to
airflow Care must be taken to prevent
bending of the aluminum fins on the copper
tubes
E-Coated Coil Cleaning
Documented routine cleaning of e-coated
coils is required to maintain coating
warranty coverage
Surface loaded fibers or dirt should be
removed prior to water rinse to prevent
restriction of airflow If unable to back wash
the side of the coil opposite of the coils
entering air side then surface loaded fibers
ELECTRIC SHOCK
Electric shock hazard Shut off all electrical power to the unit to avoid shock hazard or injury from rotating parts
WARNING
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
41
or dirt should be removed with a vacuum
cleaner If a vacuum cleaner is not available
a soft non-metallic bristle brush may be
used In either case the tool should be
applied in the direction of the fins Coil
surfaces can be easily damaged (fin edges
bent over) if the tool is applied across the
fins
Use of a water stream such as a garden
hose against a surface loaded coil will drive
the fibers and dirt into the coil This will
make cleaning efforts more difficult Surface
loaded fibers must be completely removed
prior to using low velocity clean water rinse
A monthly clean water rinse is
recommended for coils that are applied in
coastal or industrial environments to help to
remove chlorides dirt and debris It is very
important when rinsing that water
temperature is less than 130deg F and pressure
is less than 100 psig to avoid damaging the
fin edges An elevated water temperature
(not to exceed 130deg F) will reduce surface
tension increasing the ability to remove
chlorides and dirt
Quarterly cleaning is essential to extend
the life of an e-coated coil and is required
to maintain coating warranty coverage
Coil cleaning shall be part of the unitrsquos
regularly scheduled maintenance
procedures Failure to clean an e-coated coil
will void the warranty and may result in
reduced efficiency and durability
For routine quarterly cleaning first clean the
coil with the approved coil cleaner as
mentioned in the next section After
cleaning the coils with the approved
cleaning agent use the approved chloride
remover to remove soluble salts and
revitalize the unit
Recommended Coil Cleaner
The following cleaning agent assuming it is
used in accordance with the manufacturerrsquos
directions on the container for proper mixing
(41 condensers amp 81 evaporators) and
cleaning has been approved for use on e-
coated coils to remove mold mildew dust
soot greasy residue lint and other
particulate
Enviro-Coil Concentrate Part Number H-
EC01
Recommended Chloride Remover
CHLORRID DTStrade should be used to
remove soluble salts from the e-coated coil
but the directions must be followed closely
This product is not intended for use as a
COIL CLEANERS
Harsh chemicals household bleach or acid cleaners should not be used to clean outdoor or indoor e-coated coils These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating If there is dirt below the surface of the coil use the recommended coil cleaners
CAUTION
PRESSURE CLEANING
High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin andor coil damages The force of the water or air jet may bend the fin edges and increase airside pressure drop Reduced unit performance or nuisance unit shutdowns may occur
CAUTION
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
42
degreaser Any grease or oil film should first
be removed with the approved cleaning
agent
Remove Barrier - Soluble salts adhere to the
substrate For the effective use of this
product the product must be in contact with
the salts These salts may be beneath any
soils grease or dirt therefore these barriers
must be removed prior to application of this
product
Apply CHLORRID DTS - Apply directly
onto the substrate Sufficient product must
be applied uniformly across the substrate to
thoroughly wet out surface with no areas
missed This may be accomplished by use of
a pump-up sprayer or conventional spray
gun The method does not matter as long as
the entire area to be cleaned is wetted After
the substrate has been thoroughly wetted
the salts will be soluble and is now only
necessary to rinse the salts off
Rinse - It is highly recommended that a hose
be used A pressure washer on a high
pressure setting will damage the fins The
water to be used for the rinse is
recommended to be of potable quality
though a lesser quality of water may be used
if a small amount of CHLORRID DTS is
added Check with CHLORRID
International Inc for recommendations on
lesser quality rinse water
Service
If the unit will not operate correctly and a
service company is required only a
company with service technicians qualified
and experienced in both refrigerant chillers
and air conditioning are permitted to service
the systems to keep warranties in effect If
assistance is required the service technician
must contact AAON
Warranties
Please refer to the limitation of warranties in
effect at the time of purchase
Replacement Parts
Parts for AAON equipment may be obtained
by contacting your local AAON
representative When ordering parts
reference the serial number and part number
located on the external or internal nameplate
of the unit
AAON - Longview Warranty Service
and Parts Department
203 Gum Springs Rd
Longview TX 75602
Ph 903-236-4403
Fax 903-236-4463
wwwaaoncom
NOTE Before calling technician should
have model and serial number of the unit
available for the customer service
department to help answer questions
regarding the unit
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
43
Split System Refrigerant Piping Diagrams
Figure 15 - AC Split System Piping Suction Down
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
44
Figure 16 - AC Split System Piping Suction Up
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
45
Figure 17 - AC with LAC Split System Piping Suction Down
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
46
Figure 18 - AC with LAC Split System Piping Suction Up
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
47
Figure 19 - AC with Modulating Hot Gas Reheat Split System Piping Suction Down
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
48
Figure 20 - AC with Modulating Hot Gas Reheat Split System Piping Suction Up
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
49
Figure 21 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Down
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
50
Figure 22 - AC with Modulating Hot Gas Reheat Split + LAC System Piping Suction Up
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
51
Figure 23 - AC with Hot Gas Bypass Split System Piping Suction Down
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
52
Figure 24 - AC with Hot Gas Bypass Split System Piping Suction Up
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
53
Figure 25 - AC with Hot Gas Bypass + LAC Split System Piping Suction Down
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
54
Figure 26 - AC with Hot Gas Bypass + LAC Split System Piping Suction Up
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
55
Figure 27 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Down
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
56
Figure 28 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping
Suction Up
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
57
Figure 29 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Down
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
58
Figure 30 - AC with Modulating Hot Gas Reheat and Hot Gas Bypass + LAC Split System
Piping Suction Up
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
59
Figure 31 - Heat Pump Split System Piping Suction Down
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
60
Figure 32 - Heat Pump Split System Piping Suction Up
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
61
Figure 33 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Down
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
62
Figure 34 - Heat Pump with Modulating Hot Gas Reheat Split System Piping Suction Up
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
63
Figure 35 - Heat Pump with Hot Gas Bypass Split System Piping Suction Down
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
64
Figure 36 - Heat Pump with Hot Gas Bypass Split System Piping Suction Up
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
65
Figure 37 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Down
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
66
Figure 38 ndash Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System
Piping Suction Up
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
67
CF Series Startup Form
Job Name_______________________________________________
Date______________
Address______________________________________________________________________
______________________________________________________________________________
Model Number_________________________________________________________________
Serial Number_____________________________________________ Tag_______________
Startup Contractor______________________________________________________________
Address______________________________________________________________________
_______________________________________________________
Phone______________
Pre Startup Checklist
Installing contractor should verify the following items
1 Is there any visible shipping damage Yes No
2 Is the unit level Yes No
3 Are the unit clearances adequate for service and operation Yes No
4 Do all access doors open freely and are the handles operational Yes No
5 Have all shipping braces been removed Yes No
6 Have all electrical connections been tested for tightness Yes No
7 Does the electrical service correspond to the unit nameplate Yes No
8 On 208230V units has transformer tap been checked Yes No
9 Has overcurrent protection been installed to match the unit nameplate
requirement Yes No
10 Have all set screws on the fans been tightened Yes No
11 Do all fans rotate freely Yes No
Ambient Temperature
Ambient Dry Bulb Temperature ________degF
Ambient Wet Bulb Temperature ________degF
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
68
CompressorsDX Cooling
Check Rotation
Number Model L1 L2 L3
Head
Pressure
PSIG
Suction
Pressure
PSIG
Crankcase
Heater
Amps
1
2
3
4
Refrigeration System 1 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Cooling Mode
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
69
Refrigeration System 1 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 2 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 3 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Refrigeration System 4 - Heating Mode (Heat Pump Only)
Pressure Saturated
Temperature
Line
Temperature Sub-cooling Superheat
Discharge NA NA
Suction NA
Liquid NA
Condenser Fans
Alignment
Check Rotation
Nameplate Amps________
Number hp L1 L2 L3
1
2
3
4
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
70
Maintenance Log
This log must be kept with the unit It is the responsibility of the owner andor
maintenanceservice contractor to document any service repair or adjustments AAON Service
and Warranty Departments are available to advise and provide phone help for proper operation
and replacement parts The responsibility for proper start-up maintenance and servicing of the
equipment falls to the owner and qualified licensed technician
Entry Date Action Taken NameTel
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
71
Literature Change History
July 2015
Initial version
March 2016
Clarified forklift instructions and removed wording about curb mounting
June 2016
Updated CF Series Features and Options Introduction Added Feature 17 Shipping Options in
the Feature String Nomenclature Added Storage information Added Table for Service
Clearances Clarified Low Ambient section and added a picture of an adjustable fan cycle
switch Added guidelines for variable capacity compressors and tandem compressors in the line
sizing section Added double riser schematics and discussion for heat pump operation Added a
section on compressor lockouts Included heat pump charging guidelines in the Acceptable
Refrigeration Circuit Values Table Added Special Low Ambient Option Charging Instructions
Added AC with LAC Piping to show low ambient piping which is internal to the condensing
unit
March 2017
Updated Piping Diagrams because receivers are now factory installed in CF 2-7 tons
April 2017
Updated service clearances tables and added a table for coil pull Updated orientation of the CF
9-70 ton Added a note that AAON does not recommend underground refrigerant lines Added
clarification to the liquid line solenoid valve recommendation Added a double suction risers
figure Removed solenoid valve recommendation on the heat pump double risers and updated
the figures Added a suction line traps section Changed the suction flow minimum velocity for
variable compressors Changed the caution note by removing the variable capacity compressor
wording Added discharge line sizing guidelines Removed the hot gas bypass piping
considerations for evaporator below condensing unit since they are the same as for evaporator
above condensing unit Added a figure for oil return line Changed the maximum hot gas
maximum velocity from 4000 fpm to 3500 fpm Changed the sub-cooling values in the
Acceptable Refrigeration Circuit Values table Updated heat pump piping diagrams to include
suctiondischarge line traps in suction down diagrams Added all the LAC piping diagrams
October 2017
Updated digital compressor discharge up minimum velocity Updated charge information
Updated phase imbalance example Added Air Cooled Condenser Option in A1 Compressor
Style Added No Cooling Option in A5 Staging Added WattMaster VCCX
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK
AAON
203 Gum Spring Rd
Longview TX 75602-1721
Phone 903-236-4403
Fax 903-236-4463
wwwaaoncom
CF Series
Installation Operation amp
Maintenance
V45040 Rev A 171016
(ACP J00424)
It is the intent of AAON to provide accurate and current product information However in the
interest of product improvement AAON reserves the right to change pricing specifications
andor design of its product without notice obligation or liability
Copyright copy AAON all rights reserved throughout the world
AAONreg and AAONAIRE
reg are registered trademarks of AAON Inc Tulsa OK